The present invention relates to a route technology in wireless communication, and particularly to a method for changing a route in wireless communication.
With the continuous developments in wireless communication technology and the increasing requirements by wireless communication users, cellular communication systems may change from the conventional single-hop form to a multi-hop form. For example, the Institute for Electrical and Electronic Engineers (IEEE) recently proposed the introduction of relay stations (RS) into the cellular systems on account of IEEE 802.16, so as to construct a multi-hop cell structure with a cell coverage jointly provided by a base station (BS) and the surrounding multi-hop RSs thereof. FIG. 1 shows a structure diagram based on a multi-hop cell controlled by a BS. In FIG. 1, each RS as well as the BS acts as a radio access point (RAP) to serve the subscriber stations (SS)/mobile stations (MS). An SS/MS close to the BS, such as MS1, accesses the BS directly in a single-hop manner; while an SS/MS far away from the BS, such as MS2, accesses the BS in a multi-hop manner via one or more RS. It can be seen that the introduction of the RS not only broadens the area of cell coverage and extends the capacity of cell coverage but also reduces the transmit power of the SS/MS side, so as to provide high-quality wireless communication at lower costs.
In a multi-hop communication system, when the change in the position of an SS/MS or wireless signal and so on happens, the network side may need to adjust the SS/MS route, namely to perform a route change, so as to ensure a stable network service for the SS/MS. Usually, the route change comprises two types: an intracell route change and an intercell handover and so on. Of these, the intracell route change means that an SS/MS changes the RAP providing it with service within the same cell; and the intercell handover means that the SS/MS changes the RAP between different cells.
Currently some researchers propose that, during the change of a route, the BS and the RS relevant to the SS/MS requiring the route change execute an uplink measurement and gather the measurement results at the BS, and then the BS determines an intracell route change or an intercell handover for the relevant SS/MS according to the uplink measurement results.
The current methods for the route change on the basis of uplink measurements presuppose that the uplink conditions are the same as the downlink conditions, therefore the measurement results of the uplink are used to reflect the uplink and downlink. However, in practical applications, when the uplink conditions differ from those of the downlink and the uplink and the downlink are separate, the uplink measurement results cannot reflect the downlink conditions, and then the BS will use the inaccurate measurement results as a basis for changing the route, which will cause the SS/MS to be switched to an unsuitable route and lead to poor accuracy in route changing. In addition, since the timing of the action in which an SS/MS transmits information to a BS or RS through an uplink may be interrupted, when there is no information sent from SS/MS over the uplink, a BS or RS cannot execute the uplink measurement, thereby making it impossible to carry out a timely route change for an SS/MS.